Research

METHODOLOGY

METHODOLOGY

DATA COLLECTION

  1. 1. Characteristics of the researched object
  2. 2. Geodetic and dendrometric works
  3. 3. Forest type surveys
  4. 4. Mapping development stages and phases
  5. 5. Photo documentation
  6. 6. Special additional surveys

1. Characteristics of the research object

1.1 Localization and broader spatial relations

The chapter contains description of the study area localization from the perspective of surrounding settlements and administrative division, data about forest administration, data about total area and affiliation with the nature forest area (PLÍVA et ŽLÁBEK 1986).

1.2 History

Historical data about the forest stands development in the research area include information about forests’ species composition during the recorded historical development, information about game management, natural disasters, potential planting and harvesting measures and information about forest protection.

1.3 Natural conditions

1.3.1 Geology

Brief characteristics about geology are stated. Geological maps at a scale 1:50 000 published by Czech Geological survey are used.

1.3.2 Geomorphology

The chapter contains brief description of the relief, range of elevation, description of significant geomorphological features and categorization within the system of geomorphological division of the Czech Republic (DEMEK et al. 1987).

1.3.3 Climate

Climate data include overview of average monthly precipitation, precipitation in vegetation and non-vegetation season, number of days with snow cover, overview of average monthly temperature, average temperature in vegetation and non-vegetation season.

1.3.4 Hydrography

Classification of the area into hydrographic system of the Czech Republic, or characteristics of water courses in the area (VLČEK et al. 1984).

1.3.5 Biogeography

The study area is categorized according to biogeographic division of the Czech Republic (CULEK et al. 1995).

2. Geodetic and dendrometric works

2.1 Basic hardware and software

Geodetic localization of the forest stand is done by Field-Map technology (Institute of Forest Ecosystem Research, Ltd., 1999/2004). During the localization, a set of compass module MapStar (Laser Technology, Inc.), laser rangefinder and altimeter Impulse (Laser Technology, Inc.) and field laptop Hammerhead (WalkAbout Computers) are used. Researched objects of the forest stand – standing trees, lying trees, regeneration, stumps, transect, topographic measurements, additional measurements – are localized and individually described. In the Field-Map application, the objects are separated into individual layers containing only one type of the localized object.

2.2 Field-Map project

Individual layers of objects in the Field Map are recorded in a format compatible with GIS ArcView software. Created project contains all localized objects of the research plot and is divided into individual thematic layers. Therefore the project allows you to display and combine any layers from the plot in the desired scale. To more transparently visualise map sources we have created a map legend containing 306 geometric symbols for the trees. One symbol combines present tree growth form, tree species and the dynamic of its development.

2.3 Survey and description of standing trees/stems

The methodology distinguishes a tree from a stem. A tree represents an individual which comprises of one or more stems – e.g. after bifurcation or in a polycormon. A stem is a stem base which enters the calculation of timber volume (breast height diameter (DBH) exceeds 100 mm) and which occupies a distinct position in the social structure of the vegetation, e.g. a stem in a forked tree or one of the stems in a polycormon. All stems with minimal DBH of 100 mm are localized and described. Following attributes are recorded for each tree:

  • identification number of a stem
  • tree number – every tree is marked by a “birth” number of the tree to which all stems from a polycormon or stems from bifurcation belong. Thus these stems have the same tree number
  • stem position within a tree – selection from a list “Multi-stem type“ (see Appendix 2a)
  • serial stem number – indicates the serial number of a stem within a tree (e.g. stems in a forked tree will have serial numbers 1, 2)
  • breast height diameter 1,3 m above ground with an accuracy of 1 cm
  • stem height with an accuracy of 0.5 m
  • tree species – selection from a list “Species” (see Appendix 2b)
  • character of the stem condition – determines life condition of a stem, selection from a list „Stem feature“ (see Appendix 2c)
  • upper thickness of a fracture or a stump with an accuracy of 1 cm – is determined when the stem is in the form of a stump or a fracture
  • character of stem shape – determines specific stem shapes, selection from a list „Stem distinctive“ (see Appendix 2d)
  • social status of a stem in the stand – classification according to condensed Zlatník’s scale, selection from a list „Social status“ (see Appendix 2e)
  • note – additional information about health status etc.

2.4 Survey and description of lying trees/stems

Lying stems with minimum DBH of 100 mm are localized; following attributes are recorded for each stem:

  • identification number of a lying stem
  • stem number – every lying stem is marked by a “birth” number of the tree to which it belongs
  • DBH (in cm) in the length of 1,3 m from the stem base
  • length of the lying tree with an accuracy of 0.5 m
  • tree species – selection from a list „Druh_dřeviny“ (see Attachement 2b)
  • decomposition degree – a state of decomposition is determined, selection from a list „Stupeň_rozkladu“ (see Appendix 2f)
  • origin of the lying stem – selection from a list „Původ_kusu“ (see Attachment 2g)
  • note – additional information

2.5 Survey and description of regeneration

Plots with uninterrupted regeneration of trees with a minimum height of 0.1 m are localized. Each plot is characterized by these attributes:

  • identification number of the regeneration plot
  • tree species representation; representation is expressed in % of the number of individuals of each tree species
  • density of individuals in the regeneration plot, the average number of individuals per m2 is recorded
  • average height in the regeneration plot with an accuracy of 0.5 m
  • note, includes e.g. information about protection measures for restoration, damage, origin of restoration

2.6 Survey and description of stumps

Stumps – stem bases with roots remaining after the fall of a tree and with a height up to 1.5 m are localized. Each stump is characterized by these attributes:

  • identification number of a stump
  • tree species – if recognizable – selection from a list „Species“ (see Appendix 2b)
  • stump diameter (in cm) at the cutting face
  • stump origin – we distinguish a stump formed naturally and a stump form artificially which was created by logging, selection from a list „Stump origin“ (see Appendix 2h)
  • note – additional information

2.7 Survey and description of a transect

Transects are selected in the most characteristic parts of the research objects in different development stages. Following objects are localized and/or described in each transect:

  • borders of the transect; width and length are measured
  • vertical terrain profile
  • position of standing trees; position and attributes are known from the basic tree measurements
  • horizontal crown projections of individual trees
  • vertical crown projections in the north-south direction
  • vertical crown projections in the east-west direction
  • lying trees; position and attributes are known from the basic measurements of lying dead trees
  • plots with uninterrupted regeneration; position and attributes are known from the basic tree measurements
  • vertical profiles of uninterrupted regeneration
  • individuals of regeneration; attributes of tree species, height (with an accuracy of 0.1 m) and a relevant note are recorded
  • position of stumps; positions and attributes of stumps are known from the basic measurement of stumps

2.8 Topographic surveys

If there are significant topographic features such as water courses, oxbows, periodical pools, rock scree etc., they are localized if necessary and provided with notes.

2.9 Additional surveys

Additional surveys investigate objects of anthropogenic origin in the forest stand that may influence forest development. They include forest roads or paths, areas fenced against grazing, traces of past uses – e.g. plots of charcoal kilns, traces of mining activities, etc. Additional surveys include also localization of objects that have arisen in connection with the forest research, e.g. positions of soil pits, relevés, photo sites, etc. These objects are described by relevant attributes when needed.

3. Typological surveys

3.1 Phytosociological records

Field data are acquired by processing repeated phytosociological records. Plots for vegetation sampling are distributed in a way to best capture habitat and vegetation conditions of a site, i.e. they cover majority of present forest types. Identification of plots in the field is clear from their localization in the tree map. Always the same plots are assessed during repeated surveys. They are circular with a diameter of 25 m, i.e. with area of 491 m2. Phytosociological survey usually takes place in July and the summer vegetation aspect is captured. Since the same plots are used also for the assessment of soil conditions we call them permanent typological plots (PTP). For vegetation classification we use Braun-Blanquet combined classification of abundance and dominance adjusted by Zlatník (1953) in Zlatník (1976). Tree assessment is based on the classification into layers according to Zlatník (not identified) in Randuška et al. (1986). Herb layer according to Randuška et al. (1986) and Plíva (1991) includes also some shrubs and semi-shrubs (e.g. genera Hedera, Rubus, Vaccinium, Vinca). Nomenclature of vascular plants after Kubát et al. (2002) is used. Mosses or lichens are not closely monitored.

3.2 Pedological surveys

Soil conditions are assessed in selected permanent typological plots (PTP). A soil profile is dug and described in a selected area after a test survey with a boring bar. Disturbed soil samples are taken for laboratory analyses. Distribution of soil pits (or rather selection of PTP where the soil pits will be dug) should maximally represent soil conditions of the plot. Pits are therefore placed in the majority of present forest types (typological system of FMI – Anonymus 1971/1976, OPRL for specific PLO). Soil profiles are thus usually implicitly distributed along the main direction of spatial diversity of soils. Parameters of soil pits and orientation of soil head in the field concur with standard procedures (internal methodology of FMI, Rejšek 1999, Vala et al. 2002, etc.). After digging and trimming the soil head, the soil profile is photographed. The profiles are localized into the tree map with the help of Field-Map. This ensures unambiguous identification for subsequent evaluation. Soil profiles are dug approximately 2 m from the original profiles during the repeated survey.Before the profile description, general characteristics of the plot together with data related to the day of the assessment (exposition, slope, characteristics of the terrain, date, weather) are recorded. Vegetation cover is not assessed in detail since it is assessed separately during phytosociological survey. Description of the soil profile is standard (methodologies from FMI, Šarman 1984, Rejšek 1999, Vala et al. 2002). Ground water level together with rooting depth (major and minor separately) are assessed. The humus horizon (at several locations within PTP) is assessed separately. For individual horizons we usually record: thickness; depth; colour (since 2004 besides verbal description also according Munsell tables – it is evaluated in the field at the present moisture, repeated assessment of dry sample is appropriate); structure or strength of aggregates; consistency; skeleton content, its size, shape, alternatively orientation and origin; moisture; neoplasms and inclusions; reaction with HCI; transition into lower horizons (shape and gradation). Horizon nomenclature, classification of soil types and forms of humus corresponds with a valid classification system – Taxonomic classification system of soils of the Czech Republic (Němeček et al. 2001). If necessary, FAO taxonomy (FAO-ISSS-ISRIC 1998, Driessen et al. 2001) and in the case of humus taxonomy from Green et al. (1993) are used.

Soil sampling is carried out according to Rejšek (1999) and Vally et al. (2002) (not according to the Decree of Ministry of Agriculture No. 257/1998 Coll.). Disturbed samples of selected horizons including humus (when thicker, separate samples are for F and H or T and O horizons; when less thick a joint sample of F and H horizons is used) are analyzed in a laboratory.

4. Mapping development stages and phases

Mapping development stages and phases is based on the terminological and methodological works dealing with development dynamics (Korpeľ 1995, Míchal 1983, Míchal et Petříček 1989). By default, three stages of so called “small development cycle” of the central European temperate forest are distinguished – recruitment, optimum, decay, including finer structuring into phases. If there are larger disturbances which go beyond “small development cycle” they are mapped using three stages of “big development cycle” – preparatory, intermediate and closing forest. If there are localities with blocked succession they are mapped and completed with notes about the reason for blocking the succession.

5. Photo documentation

A series of direction photos is made as a part of photo documentation. The place of shot is recorded and the shot direction together with a photographed sector is localized in the GIS layer.

6. Special supplementary surveys

For specific requirements several surveys to complement the overall characteristics of the stand are carried out. These include pollen analyses, tree ring analyses, zoological surveys, etc. These surveys must be coordinated by experts from relevant fields.